In cellular networks, it is known to provide a user equipment (UE) with packet data connectivity so as to allow Internet Protocol based data transmission to or from the UE. This may for example be achieved by using the Evolved Packet System (EPS) architecture as specified by the 3rd Generation Partnership Project (3GPP). To support efficient distribution of multimedia content, such packet data connectivity may also be supplemented by support for broadcast and multicast transmission modes, as for example realized by the Multimedia Broadcast/Multicast Service (MBMS) architecture specified in 3GPP TS 23.246 V11.1.0.
In the MBMS enhanced EPS architecture, IP Multicast transmission, e.g., as specified by IETF RFC 2236, IETF RFC 3376, or IETF RFC 3810, may be used not only on the user level, by allocating an IP Multicast address to an IP Multicast group including multiple UEs, but also for transport purposes within the network. Specifically, on the M1 interface between an MBMS gateway (MBMS GW) and a Radio Access Network (RAN), a transport IP Multicast group may be defined to include multiple nodes of the RAN, and a transport IP Multicast address allocated to the transport IP Multicast group may be used to distribute data from a MBMS GW to the RAN nodes. Depending on the utilized radio access technology, such RAN nodes may be base stations of the LTE (Long Term Evolution) radio access technology, also referred to as eNB, or base station controllers of the UMTS (Universal Mobile Telecommunications System) radio access technology, also referred to as Radio Network Controller (RNC).
According to 3GPP TS 23.246, the MBMS GW allocates the IP Multicast address per MBMS bearer service. This means that a new IP Multicast address is needed for each MBMS session transmitted by the RAN nodes. Specifically in view of the fact that the number of MBMS sessions may be quite large, e.g., in the range of thousand, this may require significant resources in the involved nodes, such as in eNBs, which may need to be part of multiple IP Multicast groups and be engaged in corresponding protocol activities. Further, a large number of used IP Multicast addresses may also affect routers or switches which are used to forward the data of the IP multicast transmission in the network. For example, such routers may need to maintain and communicate information concerning the IP Multicast groups and IP Multicast routes, and the amount of information to be handled may increase considerably with the number of used IP Multicast groups.
Accordingly, there is a need for techniques which allow for efficiently implementing multicast transmission in a cellular network.